College of Bioscience and Biotechnology, Hunan Agricultural University, Changsha 410128, PR China; Hubei Key Laboratory for Processing and Application of Catalytic Materials, Huanggang Normal University, Huanggang 438000, PR China; College of Chemical Engineering, Huanggang Normal University, Huanggang 438000, PR China.
Hubei Key Laboratory for Processing and Application of Catalytic Materials, Huanggang Normal University, Huanggang 438000, PR China; College of Chemical Engineering, Huanggang Normal University, Huanggang 438000, PR China.
J Hazard Mater. 2017 Aug 5;335:92-99. doi: 10.1016/j.jhazmat.2017.04.013. Epub 2017 Apr 5.
Thidiazuron (TDZ; 1-phenyl-3-(1,2,3-thiadiazol-5-yl)urea) is one of the most widely used defoliant and easy to dissolve in surface water. Risk associated with the pesticide is not clearly defined, so it is important to remove/degrade TDZ with an efficient and environment friendly technology. Here, we investigated the use of Ag/AgCl-activated carbon (Ag/AgCl-AC) composites in photocatalytic degradation of TDZ under LED light. By the synergic effect of Ag/AgCl and AC, the optimum Ag/carbon weight ratio of 2:1 exhibited superior visible-light photocatalytic activity, the highest removal efficiency was close to 91% in pH 7 matrix. Different types of Ag/AgCl-AC composites were tested, all showed much faster photodegradation kinetics than bare Ag/AgCl in 210min. The degradation products as identified by HPLC-MS revealed that the hydroxylation by hydroxyl radicals and that of oxidation by superoxide radicals as well as holes were the two main pathways for TDZ degradation. Results revealed that the adsorption concentrated TDZ molecules and the photocatalytically generated radicals rapidly degradated TDZ, the two contributions functioned together for removal of the pollutant from water.
噻二唑脲（TDZ；1-苯基-3-（1,2,3-噻二唑-5-基）脲）是最广泛使用的脱叶剂之一，易溶于地表水。与该农药相关的风险尚未明确界定，因此，使用高效且环保的技术去除/降解 TDZ 非常重要。在这里，我们研究了在 LED 光下使用 Ag/AgCl-活性炭（Ag/AgCl-AC）复合材料光催化降解 TDZ。通过 Ag/AgCl 和 AC 的协同作用，Ag/碳的最佳重量比为 2:1 时表现出优异的可见光光催化活性，在 pH7 基质中，去除效率接近 91%。测试了不同类型的 Ag/AgCl-AC 复合材料，它们在 210min 内的光降解动力学均明显快于纯 Ag/AgCl。通过高效液相色谱-质谱（HPLC-MS）鉴定的降解产物表明，羟基自由基的羟化作用、超氧自由基和空穴的氧化作用是 TDZ 降解的两个主要途径。结果表明，吸附浓缩了 TDZ 分子，光催化生成的自由基迅速降解了 TDZ，这两种作用共同作用将污染物从水中去除。
